Two senior Secret Service agents, including a top member of President Barack Obama's protective detail, crashed a car into a White House barricade following a late-night party for retiring spokesman Ed Donovan and it's suspected they had been drinking, sources confirmed to CNN.

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Report: Two Secret Service agents under investigation

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The officers were allowed to go home after a supervisor on duty overruled on-duty law enforcement who wanted to arrest the agents and conduct sobriety tests, a U.S. law enforcement official confirmed to CNN.

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"The officers for the Secret Service who monitor the safety of the White House complex and ultimately the president and his family felt that these two individuals may have been intoxicated," Washington Post reporter Carol D. Leonnig, who broke the story, said in an interview broadcast on CNN's Situation Room with Wolf Blitzer.

The two employees have been reassigned to non-supervisory, non-operational assignments, a Secret Service official said.

A senior administration official says the White House, including President Barack Obama, is "aware of the alleged incident."

"At the request of Secret Service Director Joe Clancy, the Department of Homeland Security's Office of the Inspector General is conducting an investigation into the allegations. We're not going to comment further on this while that investigation is ongoing," the official said.

"The President is aware of the allegations and supports Director Clancy's decision to turn the investigation over to the DHS Inspector General for a thorough review," another senior administration official said.

The Secret Service gave a top Republican lawmaker a heads up earlier today before The Washington Post reported that two agents crashed a government car into White House security barriers last week after attending a party.

House Oversight Committee Chairman Jason Chaffetz told CNN that his initial understanding is that the two agents were "partying in Georgetown" when they responded to an incident at the White House.

"Drinking on the job isn't good at McDonald's and it certainly isn't good if you work for the Secret Service," he said.

Chaffetz said the agency gave him "a very short, brief heads up," and only then because the paper was going to report a story about "inebriated Secret Service agents, and obviously that's the most serious concern."

"I know there was an incident and it wasn't pretty. The details of which we need to have flushed out. Our committee will continue its investigation into the Secret Service and add this on to the list of embarrassments," he said.

Chaffetz said four whistleblowers had contacted his office about the incident in the last 48 hours, but he's not yet verified their accounts.

"They've got to get a grip on what's going on. There's obviously a deep-seated cultural problem," said Chaffetz, calling for swift discipline if warranted.

Chaffetz and the committee's top Democrat, Rep. Elijah Cummings, issued a joint-statement on Wednesday evening questioning whether further reforms are necessary to ensure the agency's integrity.

"Although recent steps have been made to bring new leadership in at the highest levels, this incident begs the question of whether that is enough," they said. "The fact that this event involved senior-level agents is not only embarrassing but exhibits a clear lack of judgment in a potentially dangerous situation."